function findPeakElement(nums: number[]): number {
    let left = 0, right = nums.length - 1;
    while (left < right) {
        let mid: number = (left + right) >> 1;
        if (nums[mid] <= nums[mid+1]) {
            left = mid +1;
        } else {
            right = mid;
        }
    }
    return left;
};